flock.cpp

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 //------------------------------------------------------------------------
// Project     : SDK Base
// Version     : 1.0
//
// Category    : Helpers
// Filename    : base/thread/source/flock.cpp
// Created by  : Steinberg, 1995
// Description : Locks
//
//-----------------------------------------------------------------------------
// LICENSE
// (c) 2023, Steinberg Media Technologies GmbH, All Rights Reserved
//-----------------------------------------------------------------------------
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//   * Redistributions of source code must retain the above copyright notice, 
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation 
//     and/or other materials provided with the distribution.
//   * Neither the name of the Steinberg Media Technologies nor the names of its
//     contributors may be used to endorse or promote products derived from this 
//     software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
// IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE  OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
//-----------------------------------------------------------------------------
 
#define DEBUG_LOCK 0
 
#include "base/thread/include/flock.h"
#include "base/source/fdebug.h"
 
//------------------------------------------------------------------------
#if SMTG_OS_WINDOWS
//------------------------------------------------------------------------
#ifndef WINVER
#define WINVER 0x0500
#endif
#ifndef _WIN32_WINNT
#define _WIN32_WINNT WINVER
#endif
 
#include <windows.h>
#include <objbase.h>
#define INIT_CS(cs) \
    InitializeCriticalSection ((LPCRITICAL_SECTION)&cs);
 
#endif // SMTG_OS_WINDOWS
 
namespace Steinberg {
namespace Base {
namespace Thread {
 
 
//------------------------------------------------------------------------
//  FLock implementation
//------------------------------------------------------------------------
FLock::FLock (const char8* /*name*/)
{
#if SMTG_PTHREADS
    pthread_mutexattr_t mutexAttr;
    pthread_mutexattr_init (&mutexAttr);
    pthread_mutexattr_settype (&mutexAttr, PTHREAD_MUTEX_RECURSIVE);
    if (pthread_mutex_init (&mutex, &mutexAttr) != 0)
        {SMTG_WARNING("mutex_init failed")}
    pthread_mutexattr_destroy (&mutexAttr);
 
#elif SMTG_OS_WINDOWS
    INIT_CS (section)
#else
#warning implement FLock!
#endif
}
 
//------------------------------------------------------------------------
FLock::~FLock ()
{
#if SMTG_PTHREADS
    pthread_mutex_destroy (&mutex);
 
#elif SMTG_OS_WINDOWS
    DeleteCriticalSection ((LPCRITICAL_SECTION)&section);
        
#endif
}
 
//------------------------------------------------------------------------
void FLock::lock ()
{
#if DEBUG_LOCK
    FDebugPrint ("FLock::lock () %x\n", this);
#endif
 
#if SMTG_PTHREADS
    pthread_mutex_lock (&mutex);
 
#elif SMTG_OS_WINDOWS
    EnterCriticalSection ((LPCRITICAL_SECTION)&section);
 
#endif
}
 
//------------------------------------------------------------------------
void FLock::unlock ()
{
#if DEBUG_LOCK
    FDebugPrint ("FLock::unlock () %x\n", this);
#endif
    
#if SMTG_PTHREADS
    pthread_mutex_unlock (&mutex);
 
#elif SMTG_OS_WINDOWS
    LeaveCriticalSection ((LPCRITICAL_SECTION)&section);
 
#endif 
}
 
//------------------------------------------------------------------------
bool FLock::trylock ()
{
#if SMTG_PTHREADS
    return pthread_mutex_trylock (&mutex) == 0;
 
#elif SMTG_OS_WINDOWS
    return TryEnterCriticalSection ((LPCRITICAL_SECTION)&section) != 0 ? true : false;
 
#else
    return false;
#endif 
}
 
} // Thread
} // Base
} // Steinberg